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Liang X, Chen W, Jiang B, Xiao CJ. Dibenzofurans from nature: Biosynthesis, structural diversity, sources, and bioactivities. Bioorg Chem 2024; 144:107107. [PMID: 38218069 DOI: 10.1016/j.bioorg.2024.107107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 11/22/2023] [Accepted: 01/06/2024] [Indexed: 01/15/2024]
Abstract
Dibenzofurans are a small class of natural products with versatile biological activities that used to be thought to come mainly from lichens and ascomycetes. In fact, they are also distributed widely in higher plants, especially in the families Rosaceae and Myrtaceae. Dibenzofurans and derivatives from lichens and ascomycetes have been well reviewed, but dibenzofurans from all biological sources in nature have not been reviewed. In this review, dibenzofurans from all natural sources have been comprehensively reviewed, and a total of 211 dibenzofurans isolated and identified from organisms between 1843 and March 2023 are categorized and discussed, including their biosynthesis, structural diversity, sources, and bioactivities.
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Affiliation(s)
- Xin Liang
- Yunnan Key Laboratory of Screening and Research on Anti-pathogenic Plant Resources from Western Yunnan, Dali University, Dali 671000, China; Institute of Materia Medica & College of Pharmacy, Dali University, Dali 671000, China
| | - Wei Chen
- Yunnan Key Laboratory of Screening and Research on Anti-pathogenic Plant Resources from Western Yunnan, Dali University, Dali 671000, China; Institute of Materia Medica & College of Pharmacy, Dali University, Dali 671000, China
| | - Bei Jiang
- Yunnan Key Laboratory of Screening and Research on Anti-pathogenic Plant Resources from Western Yunnan, Dali University, Dali 671000, China; Institute of Materia Medica & College of Pharmacy, Dali University, Dali 671000, China
| | - Chao-Jiang Xiao
- Yunnan Key Laboratory of Screening and Research on Anti-pathogenic Plant Resources from Western Yunnan, Dali University, Dali 671000, China; Institute of Materia Medica & College of Pharmacy, Dali University, Dali 671000, China.
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2
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Liu XY, Wang YN, Du JS, Chen BH, Liu KY, Feng L, Xiang GS, Zhang SY, Lu YC, Yang SC, Zhang GH, Hao B. Biosynthetic pathway of prescription bergenin from Bergenia purpurascens and Ardisia japonica. FRONTIERS IN PLANT SCIENCE 2024; 14:1259347. [PMID: 38239219 PMCID: PMC10794647 DOI: 10.3389/fpls.2023.1259347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Accepted: 12/14/2023] [Indexed: 01/22/2024]
Abstract
Bergenin is a typical carbon glycoside and the primary active ingredient in antitussive drugs widely prescribed for central cough inhibition in China. The bergenin extraction industry relies on the medicinal plant species Bergenia purpurascens and Ardisia japonica as their resources. However, the bergenin biosynthetic pathway in plants remains elusive. In this study, we functionally characterized a shikimate dehydrogenase (SDH), two O-methyltransferases (OMTs), and a C-glycosyltransferase (CGT) involved in bergenin synthesis through bioinformatics analysis, heterologous expression, and enzymatic characterization. We found that BpSDH2 catalyzes the two-step dehydrogenation process of shikimic acid to form gallic acid (GA). BpOMT1 and AjOMT1 facilitate the methylation reaction at the 4-OH position of GA, resulting in the formation of 4-O-methyl gallic acid (4-O-Me-GA). AjCGT1 transfers a glucose moiety to C-2 to generate 2-Glucosyl-4-O-methyl gallic acid (2-Glucosyl-4-O-Me-GA). Bergenin production ultimately occurs in acidic conditions or via dehydration catalyzed by plant dehydratases following a ring-closure reaction. This study for the first time uncovered the biosynthetic pathway of bergenin, paving the way to rational production of bergenin in cell factories via synthetic biology strategies.
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Affiliation(s)
- Xiang-Yu Liu
- College of Agronomy and Biotechnology, National and Local Joint Engineering Research Center on Germplasm Innovation & Utilization of Chinese Medicinal Materials in Southwest China, Key Laboratory of Medicinal Plant Biology of Yunnan Province, Yunnan Agricultural University, Kunming, Yunnan, China
- Yunnan Characteristic Plant Extraction Laboratory, Kunming, Yunnan, China
| | - Yi-Na Wang
- College of Agronomy and Biotechnology, National and Local Joint Engineering Research Center on Germplasm Innovation & Utilization of Chinese Medicinal Materials in Southwest China, Key Laboratory of Medicinal Plant Biology of Yunnan Province, Yunnan Agricultural University, Kunming, Yunnan, China
- Yunnan Characteristic Plant Extraction Laboratory, Kunming, Yunnan, China
| | - Jiang-Shun Du
- College of Agronomy and Biotechnology, National and Local Joint Engineering Research Center on Germplasm Innovation & Utilization of Chinese Medicinal Materials in Southwest China, Key Laboratory of Medicinal Plant Biology of Yunnan Province, Yunnan Agricultural University, Kunming, Yunnan, China
- Yunnan Characteristic Plant Extraction Laboratory, Kunming, Yunnan, China
| | - Bi-Huan Chen
- College of Agronomy and Biotechnology, National and Local Joint Engineering Research Center on Germplasm Innovation & Utilization of Chinese Medicinal Materials in Southwest China, Key Laboratory of Medicinal Plant Biology of Yunnan Province, Yunnan Agricultural University, Kunming, Yunnan, China
- Yunnan Characteristic Plant Extraction Laboratory, Kunming, Yunnan, China
| | - Kun-Yi Liu
- Yunnan Characteristic Plant Extraction Laboratory, Kunming, Yunnan, China
| | - Lei Feng
- College of Agronomy and Biotechnology, National and Local Joint Engineering Research Center on Germplasm Innovation & Utilization of Chinese Medicinal Materials in Southwest China, Key Laboratory of Medicinal Plant Biology of Yunnan Province, Yunnan Agricultural University, Kunming, Yunnan, China
- Yunnan Characteristic Plant Extraction Laboratory, Kunming, Yunnan, China
| | - Gui-Sheng Xiang
- College of Agronomy and Biotechnology, National and Local Joint Engineering Research Center on Germplasm Innovation & Utilization of Chinese Medicinal Materials in Southwest China, Key Laboratory of Medicinal Plant Biology of Yunnan Province, Yunnan Agricultural University, Kunming, Yunnan, China
- Yunnan Characteristic Plant Extraction Laboratory, Kunming, Yunnan, China
| | - Shuang-Yan Zhang
- College of Agronomy and Biotechnology, National and Local Joint Engineering Research Center on Germplasm Innovation & Utilization of Chinese Medicinal Materials in Southwest China, Key Laboratory of Medicinal Plant Biology of Yunnan Province, Yunnan Agricultural University, Kunming, Yunnan, China
- Yunnan Characteristic Plant Extraction Laboratory, Kunming, Yunnan, China
| | - Ying-Chun Lu
- Yunnan Characteristic Plant Extraction Laboratory, Kunming, Yunnan, China
| | - Sheng-Chao Yang
- College of Agronomy and Biotechnology, National and Local Joint Engineering Research Center on Germplasm Innovation & Utilization of Chinese Medicinal Materials in Southwest China, Key Laboratory of Medicinal Plant Biology of Yunnan Province, Yunnan Agricultural University, Kunming, Yunnan, China
- Yunnan Characteristic Plant Extraction Laboratory, Kunming, Yunnan, China
| | - Guang-Hui Zhang
- College of Agronomy and Biotechnology, National and Local Joint Engineering Research Center on Germplasm Innovation & Utilization of Chinese Medicinal Materials in Southwest China, Key Laboratory of Medicinal Plant Biology of Yunnan Province, Yunnan Agricultural University, Kunming, Yunnan, China
- Yunnan Characteristic Plant Extraction Laboratory, Kunming, Yunnan, China
| | - Bing Hao
- Yunnan Characteristic Plant Extraction Laboratory, Kunming, Yunnan, China
- College of Tobacco Science, Yunnan Agricultural University, Kunming, Yunnan, China
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Busnena BA, Beerhues L, Liu B. Biphenyls and dibenzofurans of the rosaceous subtribe Malinae and their role as phytoalexins. PLANTA 2023; 258:78. [PMID: 37689618 PMCID: PMC10492887 DOI: 10.1007/s00425-023-04228-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 08/23/2023] [Indexed: 09/11/2023]
Abstract
MAIN CONCLUSION Biphenyl and dibenzofuran phytoalexins are differentially distributed among species of the rosaceous subtribe Malinae, which includes apple and pear, and exhibit varying inhibitory activity against phytopathogenic microorganisms. Biphenyls and dibenzofurans are specialized metabolites, which are formed in species of the rosaceous subtribe Malinae upon elicitation by biotic and abiotic inducers. The subtribe Malinae (previously Pyrinae) comprises approximately 1000 species, which include economically important fruit trees such as apple and pear. The present review summarizes the current status of knowledge of biphenyls and dibenzofurans in the Malinae, mainly focusing on their role as phytoalexins. To date, 46 biphenyls and 41 dibenzofurans have been detected in 44 Malinae species. Structurally, 54 simple molecules, 23 glycosidic compounds and 10 miscellaneous structures were identified. Functionally, 21 biphenyls and 21 dibenzofurans were demonstrated to be phytoalexins. Furthermore, their distribution in species of the Malinae, inhibitory activities against phytopathogens, and structure-activity relationships were studied. The most widely distributed phytoalexins of the Malinae are the three biphenyls aucuparin (3), 2'-methoxyaucuparin (7), and 4'-methoxyaucuparin (9) and the three dibenzofurans α-cotonefuran (47), γ-cotonefuran (49), and eriobofuran (53). The formation of biphenyl and dibenzofuran phytoalexins appears to be an essential defense weapon of the Malinae against various stresses. Manipulating phytoalexin formation may enhance the disease resistance in economically important fruit trees. However, this approach requires an extensive understanding of how the compounds are formed. Although the biosynthesis of biphenyls was partially elucidated, formation of dibenzofurans remains largely unclear. Thus, further efforts have to be made to gain deeper insight into the distribution, function, and metabolism of biphenyls and dibenzofurans in the Malinae.
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Affiliation(s)
- Belnaser A Busnena
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Mendelssohnstraße 1, 38106, Braunschweig, Germany
| | - Ludger Beerhues
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Mendelssohnstraße 1, 38106, Braunschweig, Germany
| | - Benye Liu
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Mendelssohnstraße 1, 38106, Braunschweig, Germany.
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Xie L, Lu Y, Zhou Y, Hao X, Chen W. Functional Analysis of a Methyltransferase Involved in Anthocyanin Biosynthesis from Blueberries ( Vaccinium corymbosum). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:16253-16262. [PMID: 36519893 DOI: 10.1021/acs.jafc.2c06743] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Anthocyanins are natural water-soluble pigments that widely exist in plants, with various biological activities, including antioxidant, anti-obesity, and anti-diabetic activities. Currently, monomeric anthocyanins are mainly obtained through natural sources, which limits their availability. In the biosynthesis of anthocyanins, anthocyanin methyltransferases are recognized to play important roles in the water solubility and structural stability of anthocyanins. Blueberries are a rich source of anthocyanins with more than 30 chemical structures. However, the enzymes that were responsible for the methylation of anthocyanidin cores in blueberries had not been reported. Here, blueberries (Vaccinium corymbosum) have been selected as the candidate for characterization of the key enzyme. Phylogenic analysis, enzymatic activity assay, homology modeling, molecular simulation, protein expression and purification assay, site-directed mutation, isothermal titration calorimetry assay, and enzyme kinetic assay were used to identify the enzymatic function and molecular mechanism of VcOMT, which was responsible for the methylation of anthocyanidin cores. VcOMT could use delphinidin as a substrate but not cyanidin, petunidin, anthocyanins, flavonols, and flavonol glycosides. Ile191 and Glu198 were both identified as important amino acid residues for the binding interactions of anthocyanidins with VcOMT.
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Affiliation(s)
- Lianghua Xie
- Department of Traditional Chinese Medicine, Sir Run Yi yang Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou 310058, China
| | - Yang Lu
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou 310058, China
| | - Yiyang Zhou
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou 310058, China
| | - Xin Hao
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou 310058, China
| | - Wei Chen
- Department of Traditional Chinese Medicine, Sir Run Yi yang Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou 310058, China
- Ningbo Innovation Center, Zhejiang University, Ningbo 315100, China
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Busnena BA, Beuerle T, Mahnkopp-Dirks F, Winkelmann T, Beerhues L, Liu B. Formation and exudation of biphenyl and dibenzofuran phytoalexins by roots of the apple rootstock M26 grown in apple replant disease soil. PHYTOCHEMISTRY 2021; 192:112972. [PMID: 34624729 DOI: 10.1016/j.phytochem.2021.112972] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/21/2021] [Accepted: 09/26/2021] [Indexed: 06/13/2023]
Abstract
Apple replant disease (ARD) is a severe soil-borne disease frequently observed in apple tree nurseries and orchards worldwide. One of the responses of apple trees to ARD is the formation of biphenyl and dibenzofuran phytoalexins in their roots. However, there is no information on whether or not these phytoalexins are exuded into the soil. To answer this open question, a model system was established using the ARD-sensitive apple rootstock M26 (Malus × domestica Borkh. Rosaceae) and GC-MS analysis in combination with an in-house GC-MS database including retention indices. We have detected a total of 35 phytoalexins, i.e. 10 biphenyls and 25 dibenzofurans in root samples, thereby adding eight compounds to the previously reported 27 phytoalexins of Malinae species. When in vitro cultured M26 plantlets were treated with yeast extract, all the 35 phytoalexins were formed in the roots and 85.2% of the total phytoalexin amount was exuded into the culture medium. In roots of M26 plants grown in ARD soil in pot, 26 phytoalexins were detected and their exudation was demonstrated using two independent approaches of collecting root exudates. In a modified dipping experiment and a soil-hydroponic hybrid setup, the exudation rate was 39.5% and 20.6%, respectively. The exudation rates for individual phytoalexins differed, indicating controlled exudation processes. The exuded phytoalexins may play an important role in shaping the soil microbiome, which appears to greatly influence the development and severity of ARD.
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Affiliation(s)
- Belnaser A Busnena
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Mendelssohnstraße 1, 38106, Braunschweig, Germany.
| | - Till Beuerle
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Mendelssohnstraße 1, 38106, Braunschweig, Germany.
| | - Felix Mahnkopp-Dirks
- Institute of Horticultural Production Systems, Woody Plant and Propagation Physiology Section, Gottfried Wilhelm Leibniz Universität Hannover, Herrenhäuser Straße 2, 30419, Hanover, Germany.
| | - Traud Winkelmann
- Institute of Horticultural Production Systems, Woody Plant and Propagation Physiology Section, Gottfried Wilhelm Leibniz Universität Hannover, Herrenhäuser Straße 2, 30419, Hanover, Germany.
| | - Ludger Beerhues
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Mendelssohnstraße 1, 38106, Braunschweig, Germany.
| | - Benye Liu
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Mendelssohnstraße 1, 38106, Braunschweig, Germany.
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Rohr AD, Schimmel J, Liu B, Beerhues L, Guggenberger G, Winkelmann T. Identification and validation of early genetic biomarkers for apple replant disease. PLoS One 2020; 15:e0238876. [PMID: 32970702 PMCID: PMC7514092 DOI: 10.1371/journal.pone.0238876] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 08/25/2020] [Indexed: 12/19/2022] Open
Abstract
Apple replant disease (ARD) is a serious threat to producers of apple trees and fruits worldwide. The ARD etiology is not unraveled and managing options are either economically not applicable or environmentally harmful. Thus, interest is given in biomarkers that allow to indicate ARD situations at early time points in order to classify soils according to ARD severity but also to analyze the effectiveness to potential countermeasures. This study aimed at (i) identifying ARD biomarkers on the transcriptional level in root tissue by analyzing the expression of previously identified candidate genes in ARD soils of different origin and texture and (ii) testing the specificity of these marker genes to ARD. In vitro propagated M26 plantlets were submitted to a bio-test with three ARD soils, either untreated or disinfected by γ-irradiation. Expression of seven candidate genes identified in a previous transcriptomic study was investigated by RT-qPCR in a time course experiment. Already three days after planting, a prominent upregulation of the phytoalexin biosynthesis genes biphenyl synthase 3 (BIS3) and biphenyl 4-hydroxylase (B4Hb) was observed in the untreated ARD variants of all three soils. The phytoalexin composition in roots was comparable for all three soils and the total phytoalexin content correlated with the expression of BIS3 and B4Hb. The third promising candidate gene that was upregulated under ARD conditions was the ethylene-responsive transcription factor 1B-like (ERF1B). In a second experiment M26 plantlets were exposed to different abiotic stressors, namely heat, salt and nutrient starvation, and candidate gene expression was determined in the roots. The expression levels of BIS3 and B4Hb were highly and specifically upregulated in ARD soil, but not upon the abiotic stress conditions, whereas ERF1B also showed higher expression under heat stress. In conclusion, BIS3 and B4Hb are recommended as early ARD biomarkers due to their high expression levels and their high specificity.
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Affiliation(s)
- Annmarie-Deetja Rohr
- Institute of Horticultural Production Systems, Woody Plant and Propagation Physiology Section, Gottfried Wilhelm Leibniz University Hannover, Hanover, Germany
| | - Jessica Schimmel
- Institute of Soil Science, Gottfried Wilhelm Leibniz University Hannover, Hanover, Germany
| | - Benye Liu
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Ludger Beerhues
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Georg Guggenberger
- Institute of Soil Science, Gottfried Wilhelm Leibniz University Hannover, Hanover, Germany
| | - Traud Winkelmann
- Institute of Horticultural Production Systems, Woody Plant and Propagation Physiology Section, Gottfried Wilhelm Leibniz University Hannover, Hanover, Germany
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Saini SS, Gaid M, Sircar D. Benzoate-CoA ligase contributes to the biosynthesis of biphenyl phytoalexins in elicitor-treated pear cell cultures. PLANT CELL REPORTS 2020; 39:207-215. [PMID: 31713663 DOI: 10.1007/s00299-019-02484-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 10/26/2019] [Indexed: 05/09/2023]
Abstract
Benzoate-Coenzyme A ligase enzyme activity catalyzing the conversion of free benzoic acid to benzoyl-CoA was detected and biochemically characterized in the elicitor-treated pear cell cultures. Asian pear (Pyrus pyrifolia) is an economically and nutritionally important fruit-bearing tree of the subtribe Malinae. Upon pathogen attack, pears produce unique benzoate-derived biphenyl phytoalexins. The upstream biosynthesis of the biphenyl in Malinae is still incomplete. Previously, protein preparations from yeast extract-treated pear cultures were able to convert L-phenylalanine to cinnamic acid catalyzed by the activity of the phenylalanine ammonia lyase. The same extract was able to perform a C2 side-chain cleavage of cinnamic acid to benzaldehyde followed by oxidation of the latter to benzoic acid owing to the molecularly-undefined benzaldehyde synthase and benzaldehyde dehydrogenase activities, respectively. The biosynthesis of biphenyls starts with benzoate-Coenzyme A ligase (BZL), which converts benzoic acid to benzoyl-CoA. Subsequently, the previously-defined biphenyl synthase uses benzoyl-CoA to form the biphenyls. The current study reports the first time detection and characterization of BZL activity in elicitor-treated pear cell cultures. The preferred substrate was benzoic acid (Km = 62 ± 4 µM). Magnesium or manganese was prerequisite for the activity, which was enhanced by ~ 70% in the presence of potassium. Maximum BZL activity was observed 18 h post elicitation, which is in agreement with the coordinate induction reported for the enzymes in the same pathway. The induced BZL activity preceded the accumulation of biphenyls supporting its involvement in their biosynthesis.
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Affiliation(s)
- Shashank Sagar Saini
- Plant Molecular Biology Group, Biotechnology Department, Indian Institute of Technology Roorkee, Roorkee, 247 667, India
| | - Mariam Gaid
- Technische Universität Braunschweig, Institute of Pharmaceutical Biology, Mendelssohnstrasse 1, 38106, Braunschweig, Germany
- Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120, Halle (Saale), Germany
| | - Debabrata Sircar
- Plant Molecular Biology Group, Biotechnology Department, Indian Institute of Technology Roorkee, Roorkee, 247 667, India.
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Teotia D, Gaid M, Saini SS, Verma A, Yennamalli RM, Khare SP, Ambatipudi K, Mir JI, Beuerle T, Hänsch R, Roy P, Agrawal PK, Beerhues L, Sircar D. Cinnamate-CoA ligase is involved in biosynthesis of benzoate-derived biphenyl phytoalexin in Malus × domestica 'Golden Delicious' cell cultures. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 100:1176-1192. [PMID: 31437324 DOI: 10.1111/tpj.14506] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 07/31/2019] [Accepted: 08/07/2019] [Indexed: 05/09/2023]
Abstract
Apple (Malus sp.) and other genera belonging to the sub-tribe Malinae of the Rosaceae family produce unique benzoic acid-derived biphenyl phytoalexins. Cell cultures of Malus domestica cv. 'Golden Delicious' accumulate two biphenyl phytoalexins, aucuparin and noraucuparin, in response to the addition of a Venturia inaequalis elicitor (VIE). In this study, we isolated and expressed a cinnamate-CoA ligase (CNL)-encoding sequence from VIE-treated cell cultures of cv. 'Golden Delicious' (M. domestica CNL; MdCNL). MdCNL catalyses the conversion of cinnamic acid into cinnamoyl-CoA, which is subsequently converted to biphenyls. MdCNL failed to accept benzoic acid as a substrate. When scab-resistant (cv. 'Shireen') and moderately scab-susceptible (cv. 'Golden Delicious') apple cultivars were challenged with the V. inaequalis scab fungus, an increase in MdCNL transcript levels was observed in internodal regions. The increase in MdCNL transcript levels could conceivably correlate with the pattern of accumulation of biphenyls. The C-terminal signal in the MdCNL protein directed its N-terminal reporter fusion to peroxisomes in Nicotiana benthamiana leaves. Thus, this report records the cloning and characterisation of a cinnamoyl-CoA-forming enzyme from apple via a series of in vivo and in vitro studies. Defining the key step of phytoalexin formation in apple provides a biotechnological tool for engineering elite cultivars with improved resistance.
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Affiliation(s)
- Deepa Teotia
- Plant Molecular Biology Group, Biotechnology Department, Indian Institute of Technology Roorkee, Roorkee, 247667, India
| | - Mariam Gaid
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Mendelssohnstrasse 1, D-38106, Braunschweig, Germany
| | - Shashank S Saini
- Plant Molecular Biology Group, Biotechnology Department, Indian Institute of Technology Roorkee, Roorkee, 247667, India
| | - Aparna Verma
- Biotechnology Department, Indian Institute of Technology Roorkee, Roorkee, 247667, India
| | | | - Satyajeet P Khare
- Symbiosis School of Biological Sciences, Symbiosis International, Lavale, MH-412115, India
| | - Kiran Ambatipudi
- Biotechnology Department, Indian Institute of Technology Roorkee, Roorkee, 247667, India
| | - Javid Iqbal Mir
- Central Institute of Temperate Horticulture (ICAR-CITH), Srinagar, 190 005, Jammu and Kashmir, India
| | - Till Beuerle
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Mendelssohnstrasse 1, D-38106, Braunschweig, Germany
| | - Robert Hänsch
- Institute of Plant Biology, Technische Universität Braunschweig, Humboldtstrasse 1, D-38106, Braunschweig, Germany
| | - Partha Roy
- Molecular Endocrinology Group, Biotechnology Department, Indian Institute of Technology Roorkee, Roorkee, 247667, India
| | - Pawan Kumar Agrawal
- Odisha University of Agriculture and Technology, Bhubaneswar, 751003, Odisha, India
| | - Ludger Beerhues
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Mendelssohnstrasse 1, D-38106, Braunschweig, Germany
| | - Debabrata Sircar
- Plant Molecular Biology Group, Biotechnology Department, Indian Institute of Technology Roorkee, Roorkee, 247667, India
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9
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Saini SS, Teotia D, Gaid M, Sircar D. A new enzymatic activity from elicitor-treated pear cell cultures converting trans-cinnamic acid to benzaldehyde. PHYSIOLOGIA PLANTARUM 2019; 167:64-74. [PMID: 30417393 DOI: 10.1111/ppl.12871] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 10/26/2018] [Accepted: 11/06/2018] [Indexed: 05/09/2023]
Abstract
Cell cultures of Asian pear (Pyrus pyrifolia) are known to produce benzoate-derived biphenyl phytoalexins upon elicitor treatment. Although the downstream pathway for biphenyl phytoalexin biosynthesis is almost known, the upstream route of benzoic acid biosynthesis in pear has not been completely elucidated. In the present work, we report benzaldehyde synthase (BS) activity from yeast extract-treated cell suspension cultures of P. pyrifolia. BS catalyzes the in vitro conversion of trans-cinnamic acid to benzaldehyde using a non-oxidative C2 -side chain cleavage mechanism. The enzyme activity was strictly dependent on the presence of a reducing agent, dithiothreitol being preferred. C2 -side chain shortening of the cinnamic acid backbone resembled the mechanisms catalyzed by 4-hydroxybenzaldehyde synthase (HBS) activity in Vanilla planifolia and salicylaldehyde synthase (SAS) activity in tobacco and apple cell cultures. A basal BS activity was also observed in the non-elicited cell cultures. Upon yeast extract-treatment, a 13-fold increase in BS activity was observed when compared to the non-treated control cells. Moreover, feeding of the cell cultures with trans-cinnamic acid, the substrate for BS, resulted in an enhanced level of noraucuparin, a biphenyl phytoalexin. Comparable accumulation of noraucuparin was observed upon feeding of benzaldehyde, the BS product. The preferred substrate for BS was found to be trans-cinnamic acid, for which the apparent Km and Vmax values were 0.5 mM and 50.7 pkat mg-1 protein, respectively. Our observations indicate the contribution of BS to benzoic acid biosynthesis in Asian pear via the CoA-independent and non-β-oxidative route.
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Affiliation(s)
- Shashank S Saini
- Plant Molecular Biology Group, Biotechnology Department, Indian Institute of Technology Roorkee, Roorkee, 247 667, India
| | - Deepa Teotia
- Plant Molecular Biology Group, Biotechnology Department, Indian Institute of Technology Roorkee, Roorkee, 247 667, India
| | - Mariam Gaid
- Institut für Pharmazeutische Biologie, Technische Universität Braunschweig, D-38106, Braunschweig, Germany
| | - Debabrata Sircar
- Plant Molecular Biology Group, Biotechnology Department, Indian Institute of Technology Roorkee, Roorkee, 247 667, India
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Sarkate A, Saini SS, Gaid M, Teotia D, Mir JI, Agrawal PK, Beerhues L, Sircar D. Molecular cloning and functional analysis of a biphenyl phytoalexin-specific O-methyltransferase from apple cell suspension cultures. PLANTA 2019; 249:677-691. [PMID: 30357505 DOI: 10.1007/s00425-018-3031-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 10/18/2018] [Indexed: 06/08/2023]
Abstract
This manuscript describes the cloning and functional characterization of a biphenyl phytoalexin biosynthetic gene, 3,5-dihydroxybiphenyl O-methyltransferase from elicitor-treated cell cultures of scab resistant apple cultivar 'Florina'. Apples belong to the subtribe Malinae of the Rosaceae family. Biphenyls and dibenzofurans are the specialized phytoalexins of Malinae, of which aucuparin is the most widely distributed biphenyl. The precursor of aucuparin, 3,5-dihydroxybiphenyl, is a benzoate-derived polyketide, which is formed by the sequential condensation of three molecules of malonyl-CoA and one molecule of benzoyl-CoA in a reaction catalyzed by biphenyl synthase (BIS). This 3,5-dihydroxybiphenyl then undergoes sequential 5-O-methylation, 4-hydroxylation, and finally 3-O-methylation to form aucuparin. A cDNA encoding O-methyltransferase (OMT) was isolated and functionally characterized from the cell cultures of scab-resistant apple cultivar 'Florina' (Malus domestica cultivar 'Florina'; MdOMT) after treatment with elicitor prepared from the apple scab causing fungus Venturia inaequalis. MdOMT catalyzed the regiospecific O-methylation of 3,5-dihydroxybiphenyl at the 5-position to form 3-hydroxy-5-methoxybiphenyl. The enzyme showed absolute substrate preference for 3,5-dihydroxybiphenyl. The elicitor-treated apple cell cultures showed transient increases in the MdOMT (GenBank ID MF740747) and MdBIS3 (GenBank ID JQ390523) transcript levels followed by the accumulation of biphenyls (aucuparin and noraucuparin) and dibenzofuran (eriobofuran) phytoalexins. MdOMT fused with N- and C-terminal yellow fluorescent protein showed cytoplasmic localization in the epidermis of Nicotiana benthamiana leaves. In scab inoculated greenhouse-grown 'Florina' plants, the expression of MdOMT was transiently induced in the stem followed by the accumulation of biphenyl phytoalexins.
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Affiliation(s)
- Amol Sarkate
- Plant Molecular Biology Group, Biotechnology Department, Indian Institute of Technology Roorkee, Roorkee, 247667, India
| | - Shashank Sagar Saini
- Plant Molecular Biology Group, Biotechnology Department, Indian Institute of Technology Roorkee, Roorkee, 247667, India
| | - Mariam Gaid
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Mendelssohnstrasse 1, 38106, Braunschweig, Germany
| | - Deepa Teotia
- Plant Molecular Biology Group, Biotechnology Department, Indian Institute of Technology Roorkee, Roorkee, 247667, India
| | - Javid Iqbal Mir
- Plant Biotechnology Department, Central Institute of Temperate Horticulture (ICAR-CITH), Srinagar, 190005, Jammu and Kashmir, India
| | | | - Ludger Beerhues
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Mendelssohnstrasse 1, 38106, Braunschweig, Germany
| | - Debabrata Sircar
- Plant Molecular Biology Group, Biotechnology Department, Indian Institute of Technology Roorkee, Roorkee, 247667, India.
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11
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Reim S, Rohr AD, Winkelmann T, Weiß S, Liu B, Beerhues L, Schmitz M, Hanke MV, Flachowsky H. Genes Involved in Stress Response and Especially in Phytoalexin Biosynthesis Are Upregulated in Four Malus Genotypes in Response to Apple Replant Disease. FRONTIERS IN PLANT SCIENCE 2019; 10:1724. [PMID: 32180775 PMCID: PMC7059805 DOI: 10.3389/fpls.2019.01724] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Accepted: 12/09/2019] [Indexed: 05/17/2023]
Abstract
Apple replant disease (ARD) is a soil-borne disease, which is of particular importance for fruit tree nurseries and fruit growers. The disease manifests by a poor vegetative development, stunted growth, and reduced yield in terms of quantity and quality, if apple plants (usually rootstocks) are replanted several times at the same site. Genotype-specific differences in the reaction of apple plants to ARD are documented, but less is known about the genetic mechanisms behind this symptomatology. Recent transcriptome analyses resulted in a number of candidate genes possibly involved in the plant response. In the present study, the expression of 108 selected candidate genes was investigated in root and leaf tissue of four different apple genotypes grown in untreated ARD soil and ARD soil disinfected by γ-irradiation originating from two different sites in Germany. Thirty-nine out of the 108 candidate genes were differentially expressed in roots by taking a p-value of < 0.05 and a fold change of > 1.5 as cutoff. Sixteen genes were more than 4.5-fold upregulated in roots of plants grown in ARD soil. The four genes MNL2 (putative mannosidase); ALF5 (multi antimicrobial extrusion protein); UGT73B4 (uridine diphosphate (UDP)-glycosyltransferase 73B4), and ECHI (chitin-binding) were significantly upregulated in roots. These genes seem to be related to the host plant response to ARD, although they have never been described in this context before. Six of the highly upregulated genes belong to the phytoalexin biosynthesis pathway. Their genotype-specific gene expression pattern was consistent with the phytoalexin content measured in roots. The biphenyl synthase (BIS) genes were found to be useful as early biomarkers for ARD, because their expression pattern correlated well with the phenotypic reaction of the Malus genotypes investigated.
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Affiliation(s)
- Stefanie Reim
- Institute for Breeding Research on Fruit Crops, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, Dresden, Germany
| | - Annmarie-Deetja Rohr
- Institute of Horticultural Production Systems, Woody Plant and Propagation Physiology Section, Gottfried Wilhelm Leibniz University Hannover, Hanover, Germany
| | - Traud Winkelmann
- Institute of Horticultural Production Systems, Woody Plant and Propagation Physiology Section, Gottfried Wilhelm Leibniz University Hannover, Hanover, Germany
- *Correspondence: Traud Winkelmann,
| | - Stefan Weiß
- Institute of Horticultural Production Systems, Woody Plant and Propagation Physiology Section, Gottfried Wilhelm Leibniz University Hannover, Hanover, Germany
| | - Benye Liu
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Ludger Beerhues
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Michaela Schmitz
- Department of Natural Sciences, Hochschule Bonn-Rhein-Sieg, Rheinbach, Germany
| | - Magda-Viola Hanke
- Institute for Breeding Research on Fruit Crops, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, Dresden, Germany
| | - Henryk Flachowsky
- Institute for Breeding Research on Fruit Crops, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, Dresden, Germany
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12
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Wern C, Ehrenreich C, Joosten D, Stein TV, Buchholz H, König B. Rapid Access to Bi- and Tri-Functionalized Dibenzofurans and their Application in Selective Suzuki-Miyaura Cross Coupling Reactions. European J Org Chem 2018. [DOI: 10.1002/ejoc.201801286] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Caroline Wern
- Faculty of Chemistry and Pharmacy; University of Regensburg; Universitaetsstraße 31 93053 Regensburg Germany
- Performance Materials Division; Merck KGaA; Frankfurter Straße 250 64293 Darmstadt Germany
| | - Christian Ehrenreich
- Performance Materials Division; Merck KGaA; Frankfurter Straße 250 64293 Darmstadt Germany
| | - Dominik Joosten
- Performance Materials Division; Merck KGaA; Frankfurter Straße 250 64293 Darmstadt Germany
| | - Thorsten vom Stein
- Performance Materials Division; Merck KGaA; Frankfurter Straße 250 64293 Darmstadt Germany
| | - Herwig Buchholz
- Performance Materials Division; Merck KGaA; Frankfurter Straße 250 64293 Darmstadt Germany
| | - Burkhard König
- Faculty of Chemistry and Pharmacy; University of Regensburg; Universitaetsstraße 31 93053 Regensburg Germany
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13
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Stewart C, Woods K, Macias G, Allan AC, Hellens RP, Noel JP. Molecular architectures of benzoic acid-specific type III polyketide synthases. Acta Crystallogr D Struct Biol 2017; 73:1007-1019. [PMID: 29199980 PMCID: PMC5713876 DOI: 10.1107/s2059798317016618] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 11/17/2017] [Indexed: 11/23/2022] Open
Abstract
Biphenyl synthase and benzophenone synthase constitute an evolutionarily distinct clade of type III polyketide synthases (PKSs) that use benzoic acid-derived substrates to produce defense metabolites in plants. The use of benzoyl-CoA as an endogenous substrate is unusual for type III PKSs. Moreover, sequence analyses indicate that the residues responsible for the functional diversification of type III PKSs are mutated in benzoic acid-specific type III PKSs. In order to gain a better understanding of structure-function relationships within the type III PKS family, the crystal structures of biphenyl synthase from Malus × domestica and benzophenone synthase from Hypericum androsaemum were compared with the structure of an archetypal type III PKS: chalcone synthase from Malus × domestica. Both biphenyl synthase and benzophenone synthase contain mutations that reshape their active-site cavities to prevent the binding of 4-coumaroyl-CoA and to favor the binding of small hydrophobic substrates. The active-site cavities of biphenyl synthase and benzophenone synthase also contain a novel pocket associated with their chain-elongation and cyclization reactions. Collectively, these results illuminate structural determinants of benzoic acid-specific type III PKSs and expand the understanding of the evolution of specialized metabolic pathways in plants.
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Affiliation(s)
- Charles Stewart
- Howard Hughes Medical Institute, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Macromolecular X-ray Crystallography Facility, Office of Biotechnology, Iowa State University, 0202 Molecular Biology Building, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Kate Woods
- Howard Hughes Medical Institute, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Greg Macias
- Howard Hughes Medical Institute, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Andrew C. Allan
- The New Zealand Institute for Plant and Food Research Limited (PFR), Auckland, New Zealand
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Roger P. Hellens
- The New Zealand Institute for Plant and Food Research Limited (PFR), Auckland, New Zealand
- Queensland University of Technology, Brisbane, Queensland 4001, Australia
| | - Joseph P. Noel
- Howard Hughes Medical Institute, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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14
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Weiß S, Liu B, Reckwell D, Beerhues L, Winkelmann T. Impaired defense reactions in apple replant disease-affected roots of Malus domestica 'M26'. TREE PHYSIOLOGY 2017; 37:1672-1685. [PMID: 29036594 DOI: 10.1093/treephys/tpx108] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 08/12/2017] [Indexed: 05/08/2023]
Abstract
A soil- and site-dependent complex of diverse microbial populations causes apple replant disease (ARD), which leads to economic losses for tree nurseries and apple producers due to reduced plant growth and diminished fruit yields. Soil fumigation has been widely used to mitigate ARD, but the application of these chemicals is restricted in the European Union. Hence, other counteractions have to be developed. Genomics-based breeding may be used to select ARD-tolerant genotypes; however, molecular responses of ARD are not well understood. Recent studies revealed that biotic stress-associated genes involved in typical defense reactions are activated but do not result in an adequate response to ARD. The objective of this study was to analyze selected responsive genes in a time-course experiment to test for expression kinetics. Cultivating the ARD-susceptible apple rootstock 'M26' on ARD-affected soil resulted in significantly reduced growth as early as 7 days after planting. Genes involved in phytoalexin biosynthesis were upregulated in ARD samples as early as 3 days after planting and reached up to 26-fold changes at Day 10, which resulted in high amounts of 3-hydroxy-5-methoxybiphenyl, aucuparin, noraucuparin, 2-hydroxy-4-methoxydibenzofuran, 2'-hydroxyaucuparin and noreriobofuran. For the first time, these phytoalexins were detected, identified and quantified in apple roots. The lack of a sufficient defense response may be due to impaired sequestration and/or exudation of the potentially cytotoxic phytoalexins and perturbed formation of reactive oxygen species, leading to root damage in ARD soils. The findings provide a basis for comparative studies of the defense processes in more ARD-tolerant rootstocks.
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Affiliation(s)
- Stefan Weiß
- Leibniz Universität Hannover, Institute of Horticultural Production Systems, Section of Woody Plant and Propagation Physiology, Herrenhäuser Str. 2, D-30419 Hannover, Germany
| | - Benye Liu
- Technische Universität Braunschweig, Institute of Pharmaceutical Biology, Mendelssohnstrasse 1, D-38106 Braunschweig, Germany
| | - Dennis Reckwell
- Technische Universität Braunschweig, Institute of Pharmaceutical Biology, Mendelssohnstrasse 1, D-38106 Braunschweig, Germany
| | - Ludger Beerhues
- Technische Universität Braunschweig, Institute of Pharmaceutical Biology, Mendelssohnstrasse 1, D-38106 Braunschweig, Germany
| | - Traud Winkelmann
- Leibniz Universität Hannover, Institute of Horticultural Production Systems, Section of Woody Plant and Propagation Physiology, Herrenhäuser Str. 2, D-30419 Hannover, Germany
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15
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Weiß S, Bartsch M, Winkelmann T. Transcriptomic analysis of molecular responses in Malus domestica 'M26' roots affected by apple replant disease. PLANT MOLECULAR BIOLOGY 2017; 94:303-318. [PMID: 28424966 DOI: 10.1007/s11103-017-0608-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 03/23/2017] [Indexed: 05/21/2023]
Abstract
Gene expression studies in roots of apple replant disease affected plants suggested defense reactions towards biotic stress to occur which did not lead to adequate responses to the biotic stressors. Apple replant disease (ARD) leads to growth inhibition and fruit yield reduction in replanted populations and results in economic losses for tree nurseries and fruit producers. The etiology is not well understood on a molecular level and causal agents show a great diversity indicating that no definitive cause, which applies to the majority of cases, has been found out yet. Hence, it is pivotal to gain a better understanding of the molecular and physiological reactions of the plant when affected by ARD and later to overcome the disease, for example by developing tolerant rootstocks. For the first time, gene expression was investigated in roots of ARD affected plants employing massive analysis of cDNA ends (MACE) and RT-qPCR. In reaction to ARD, genes in secondary metabolite production as well as plant defense, regulatory and signaling genes were upregulated whereas for several genes involved in primary metabolism lower expression was detected. For internal verification of MACE data, candidate genes were tested via RT-qPCR and a strong positive correlation between both datasets was observed. Comparison of apple 'M26' roots cultivated in ARD soil or γ-irradiated ARD soil suggests that typical defense reactions towards biotic stress take place in ARD affected plants but they did not allow responding to the biotic stressors attack adequately, leading to the observed growth depressions in ARD variants.
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Affiliation(s)
- Stefan Weiß
- Institute of Horticultural Production Systems, Section of Woody Plant and Propagation Physiology, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419, Hannover, Germany
| | - Melanie Bartsch
- Institute of Horticultural Production Systems, Section of Woody Plant and Propagation Physiology, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419, Hannover, Germany
| | - Traud Winkelmann
- Institute of Horticultural Production Systems, Section of Woody Plant and Propagation Physiology, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419, Hannover, Germany.
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16
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Chizzali C, Swiddan AK, Abdelaziz S, Gaid M, Richter K, Fischer TC, Liu B, Beerhues L. Expression of Biphenyl Synthase Genes and Formation of Phytoalexin Compounds in Three Fire Blight-Infected Pyrus communis Cultivars. PLoS One 2016; 11:e0158713. [PMID: 27410389 PMCID: PMC4943715 DOI: 10.1371/journal.pone.0158713] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 05/17/2016] [Indexed: 01/28/2023] Open
Abstract
Pear (Pyrus communis) is an economically important fruit crop. Drops in yield and even losses of whole plantations are caused by diseases, most importantly fire blight which is triggered by the bacterial pathogen Erwinia amylovora. In response to the infection, biphenyls and dibenzofurans are formed as phytoalexins, biosynthesis of which is initiated by biphenyl synthase (BIS). Two PcBIS transcripts were cloned from fire blight-infected leaves and the encoded enzymes were characterized regarding substrate specificities and kinetic parameters. Expression of PcBIS1 and PcBIS2 was studied in three pear cultivars after inoculation with E. amylovora. Both PcBIS1 and PcBIS2 were expressed in 'Harrow Sweet', while only PcBIS2 transcripts were detected in 'Alexander Lucas' and 'Conference'. Expression of the PcBIS genes was observed in both leaves and the transition zone of the stem; however, biphenyls and dibenzofurans were only detected in stems. The maximum phytoalexin level (~110 μg/g dry weight) was observed in the transition zone of 'Harrow Sweet', whereas the concentrations were ten times lower in 'Conference' and not even detectable in 'Alexander Lucas'. In 'Harrow Sweet', the accumulation of the maximum phytoalexin level correlated with the halt of migration of the transition zone, whereby the residual part of the shoot survived. In contrast, the transition zones of 'Alexander Lucas' and 'Conference' advanced down to the rootstock, resulting in necrosis of the entire shoots.
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Affiliation(s)
- Cornelia Chizzali
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Mendelssohnstr. 1, 38106, Braunschweig, Germany
| | - Asya K. Swiddan
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Mendelssohnstr. 1, 38106, Braunschweig, Germany
| | - Sahar Abdelaziz
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Mendelssohnstr. 1, 38106, Braunschweig, Germany
| | - Mariam Gaid
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Mendelssohnstr. 1, 38106, Braunschweig, Germany
| | - Klaus Richter
- Julius Kühn Institute, Federal Research Centre for Cultivated Plants, Institute for Resistance Research and Stress Tolerance, Erwin-Baur-Str. 27, 06484, Quedlinburg, Germany
| | - Thilo C. Fischer
- Biotechnology of Natural Products, Life Science Center Weihenstephan, Technische Universität München, Liesel-Beckmann-Str. 1, 85354, Freising, Germany
| | - Benye Liu
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Mendelssohnstr. 1, 38106, Braunschweig, Germany
| | - Ludger Beerhues
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Mendelssohnstr. 1, 38106, Braunschweig, Germany
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